ST. LOUIS (DTN) -- Crops began to vanish mysteriously a decade ago on Lucas Criswell's no-till farm in central Pennsylvania.

"Things just started to disappear," the Lewisburg, Pa., farmer recalls. "You'd see a soybean plant one day, and the next day it would be gone."

Only by creeping into his fields at dusk and dawn did Criswell finally identify the thief slipping through his 1,800 no-till acres of corn, soybean, wheat and rye. "Slugs -- all different sizes, big ones, little ones," he told DTN. "You'll see a slime trail on the plant that kind of glistens. It's a little ...